1. FIELD OF THE INVENTION
This invention relates to a resin composition, containing an elastomer and moldings of a sheet or the like.
2. DESCRIPTION OF THE RELATED ART
Conventionally, a component molded to contain, for example, polyvinyl chloride as materials is used for door trims of vehicles, console-boxes, steering wheel grips of vehicles and so on. Rubber undergoing a cross-linking treatment with vulcanization is used for golf clubs and grips of ski poles. Since most of them consist of a single component material, the feel, when touched by a hand wet with perspiration or the like, sometimes differs from that of a dry hand. Depending upon the changed feel as described above, the feel characteristic of the resin is felt on the dry hand.
Further, environmental issues, caused by chlorine in polyvinyl chloride, which is produced in the waste treatment of spend resin moldings, have been presented and measures against the environmental issues are demanded. As an alternative to polyvinyl chloride, the use of a resin thermoplastic elastomer (TPE) is suggested, and predominately, the use of an olefin thermoplastic elastomer (TPO).
The feel of a product consisting of a TPO element includes a feeling of stickiness or a feeling of slipperiness. As a remedy against it, an attempt has been made to improve the feel by including an inorganic filler such as talc powder. The feelings of stickiness and slipperiness, however, are not resolved sufficiently, if anything, it tends to decrease the durability against friction due to the inorganic filler.
Moldings blending resin materials with a silicone have also been proposed (see Japanese Patent Application Laid-open No. Sho 58-142925 and the like). According to the aforementioned moldings, however, durability against friction is protected but the feelings of stickiness and slipperiness are not extensively improved.
A resin composition according to the present invention is characterized by including: a thermoplastic elastomer; a natural organic material; and a silicone.
As the thermoplastic elastomer, an olefin thermoplastic elastomer can be used.
An ethylene-propylene copolymer, an ethylene-propylene-diene copolymer and so on can be named as specific examples of the olefin thermoplastic elastomer.
Further, as the thermoplastic elastomer, a styrene thermoplastic elastomer can be also used.
A styrene-butadiene copolymer, a styrene-ethylene-butadiene copolymer and so on can be named as specific examples of the styrene thermoplastic elastomer.
As the natural organic material, silk, cellulose, collagen, wool, keratin, hemp, cotton, chitin, chitosan, betaine, egg shell membrane or the like can be used. Further, the aforementioned examples of the natural organic material can be used by being combined with plural examples thereof.
It is advisable that the content of the natural organic material is 5 wt % to 30 wt %. If the natural organic material is less than 5 wt %, an excellent feel, durability against friction, and moisture inhalation-exhalation cannot be obtained. If the natural organic content is more than 30 wt %, the soft property of the resin is damaged.
Where the natural organic material is in a fine powder state, it is advisable that the particle size of the natural organic material is less than 300 xcexcm. An excellent feel is hard to obtain from a particle size of more than 300 xcexcm.
It is advisable that the content of the silicone is 0.3 wt % to 10 wt %, more preferably, 0.5 wt % to 8 wt %. A silicone content of less than 0.3 wt. % is insufficient in improving the durability against friction. A silicone content of more than 10 wt % allows the mold-processability to decrease markedly.
Incidentally, required additives, such. as a, dispersing agent, a stabilizing agent, a lubricant or the like, may be added into the resin composition.
Moldings according to the present invention are formed by using the aforementioned resin composition.
Types of the moldings are selected, for example, to be sheet-shaped moldings, bottle shaped moldings, and so on.
The sheet-shaped moldings can be obtained by a calendar molding method, an extrusion molding method, or the like by using the aforementioned resin composition. Complicatedly shaped moldings (including moldings of a multi layered structure) can be obtained by an injection molding method.
The bottle-shaped moldings can be obtained by a blow molding method by using the aforementioned resin composition.
Since the moldings according to the present invention are molded by using the aforementioned resin composition, the moldings have an excellent moisture inhalation-exhalation, friction and touch-feeling, and furthermore, have a suitable hardness.